Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 45, NWS Austin/San Antonio, TX

August 2, 2021Hays County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Aug 2, 2021, 6:52 AM CDT for Hays County, Texas. It was in force for 3 hr. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 2, 2021, 6:52 AM CDT (11:52 UTC)
Expired: Aug 2, 2021, 10:00 AM CDT
In force: 3 hr
Issued by: NWS Austin/San Antonio, TX
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Hays County, TX

The radar

The Austin/San Antonio radar (KEWX), 35 km from the middle of the area, began a volume at 11:56 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where	Remark
Aug 2, 8:15 AM CDT	FLASH FLOOD	5 S Driftwood, TX	ROLLING OAKS DRIVE AT YORK CREEK CLOSED DUE TO FLOODING.
Aug 2, 8:50 AM CDT	FLASH FLOOD	3 Ese Wimberley, TX	LITTLE ARKANSAS RD AT BLANCO RIVER CLOSED DUE TO FLOODING.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 00:00Z, 11.9 hours before the alert went out and 263 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1117 J/kg
Mixed-layer CIN: -99 J/kg
Mixed-layer LCL: 1455 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 18 m²/s²
0-3 km storm-relative helicity: 84 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -1.6

Open this sounding in Storm Lab

The text

As transmitted.

267 
WGUS54 KEWX 021152
FFWEWX
TXC209-021500-
/O.NEW.KEWX.FF.W.0045.210802T1152Z-210802T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
652 AM CDT Mon Aug 2 2021

The National Weather Service in Austin/San Antonio has issued a

* Flash Flood Warning for...
  Central Hays County in south central Texas...

* Until 1000 AM CDT.

* At 652 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 4 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Wimberley and Hays City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

Stay away or be swept away. River banks and culverts can become 
unstable and unsafe.

&&

LAT...LON 3000 9794 2997 9798 2995 9801 2996 9804
      2996 9808 3000 9809 3003 9810 3007 9809
      3008 9805 3010 9801 3010 9796 3005 9792

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

AAT

The office that day

Everything else NWS Austin/San Antonio, TX issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 1, 7:53 PM CDT	Areal Flood Advisory	EWX	Bandera, Real	3 hr
Aug 1, 11:02 PM CDT	Areal Flood Advisory	EWX	Kendall	3 hr
Aug 2, 12:27 AM CDT	Areal Flood Advisory	EWX	Bastrop, Hays, Travis	3 hr
Aug 2, 3:45 AM CDT	Areal Flood Advisory	EWX	Comal, Guadalupe, Hays	4 hr
Aug 2, 3:53 AM CDT	Areal Flood Advisory	EWX	Edwards, Kinney	4 hr
Aug 2, 4:09 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Comal, Guadalupe	4 hr
Aug 2, 4:13 AM CDT	Areal Flood Advisory	EWX	Uvalde	4 hr
Aug 2, 5:41 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Guadalupe	4 hr
Aug 2, 5:45 AM CDT	Areal Flood Advisory	EWX	Bexar, Guadalupe, Wilson	3 hr
Aug 2, 5:51 AM CDT	Areal Flood Advisory	EWX	Bandera, Real	3 hr
Aug 2, 5:57 AM CDT	Areal Flood Advisory	EWX	Comal, Hays	4 hr
Aug 2, 6:37 AM CDT	Areal Flood Advisory	EWX	Bandera, Kerr, Medina	4 hr
Aug 2, 6:37 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Comal	5 hr
Aug 2, 7:15 AM CDT	Areal Flood Advisory	EWX	Bandera, Bexar, Comal, Kendall, Kerr, Medina	5 hr
Aug 2, 7:29 AM CDT	Special Weather Statement	EWX	Bexar	46 min
Aug 2, 7:47 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Bexar, Comal, Kendall	4 hr
Aug 2, 8:13 AM CDT	Areal Flood Advisory	EWX	Kinney	3 hr
Aug 2, 8:15 AM CDT	Areal Flood Advisory	EWX	Bastrop, Lee, Travis, Williamson	5 hr
Aug 2, 8:18 AM CDT	Special Weather Statement	EWX	Bexar, Comal	42 min
Aug 2, 8:26 AM CDT	Areal Flood Advisory	EWX	Bexar, Comal, Kendall	4 hr
Aug 2, 8:36 AM CDT	Areal Flood Advisory	EWX	Bexar	4 hr
Aug 2, 9:16 AM CDT	Areal Flood Advisory	EWX	Blanco, Hays, Travis	3 hr
Aug 2, 10:25 AM CDT	Areal Flood Advisory	EWX	Kinney, Maverick, Uvalde, Zavala	3 hr
Aug 2, 2:45 PM CDT	Areal Flood Advisory	EWX	Bandera, Edwards, Kerr, Real, Val Verde	3 hr
Aug 2, 4:56 PM CDT	Areal Flood Advisory	EWX	Travis, Williamson	3 hr
Aug 2, 5:12 PM CDT	Areal Flood Advisory	EWX	Blanco, Hays	3 hr
Aug 2, 6:19 PM CDT	Areal Flood Advisory	EWX	Caldwell, Hays, Travis	2 hr

Nearby

Flash Flood Warnings in Texas, 2021 Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.